Mechanosynthesis and Related Techniques
Scanning Probe Microscopy (SPM, in which we include all related techniques such as AFM, STM and others) laboratories have been manipulating individual atoms and molecules for decades. (Eigler and Schweizer, “Positioning Single Atoms with a Scanning Tunnelling Microscope,” Nature. 1990. 344:524-526; Eigler, Lutz et al., “An atomic switch realized with the scanning tunneling microscope,” Nature. 1991. 352:600-603; Stroscio and Eigler, “Atomic and Molecular Manipulation with the Scanning Tunneling Microscope,” Science. 1991. 254:1319-1326; Meyer, Neu et al., “Controlled lateral manipulation of single molecules with the scanning tunneling microscope,” Applied Physics A. 1995. 60:343-345; MEYER, NEU et al., “Building Nanostructures by Controlled Manipulation of Single Atoms and Molecules with the Scanning Tunneling Microscope,” phys Stat Sol (b). 1995. 192:313-324; Bartels, Meyer et al., “Basic Steps of Lateral Manipulation of Single Atoms and Diatomic Clusters with a Scanning Tunneling Microscope Tip,” PHYSICAL REVIEW LETTERS. 1997. 79:697-700; Bartels, Meyer et al., “Controlled vertical manipulation of single CO molecules with the scanning tunneling microscope: A route to chemical contrast,” Applied Physics Letters. 1997. 71:213; Huang and Yamamoto, “Physical mechanism of hydrogen deposition from a scanning tunneling microscopy tip,” Appl. Phys. A. 1997. 64:R419-R422; Bartels, Meyer et al., “Dynamics of Electron-Induced Manipulation of Individual CO Molecules on Cu(111),” PHYSICAL REVIEW LETTERS. 1998. 80; Ho and Lee, “Single bond formation and characterization with a scanning tunneling microscope,” Science 1999.1719-1722; Hersam, Guisinger et al., “Silicon-based molecular nanotechnology,” Nanotechnology. 2000; Hersam, Guisinger et al., “Silicon-based molecular nanotechnology,” Nanotechnology. 2000. 11:70; Hla, Bartels et al., “Inducing All Steps of a Chemical Reaction with the Scanning Tunneling Microscope Tip—Towards Single Molecule Engineering,” PHYSICAL REVIEW LETTERS. 2000. 85:2777-2780; Lauhon and Ho, “Control and Characterization of a Multistep Unimolecular Reaction,” PHYSICAL REVIEW LETTERS. 2000. 84:1527-1530; Oyabu, Custance et al., “Mechanical vertical manipulation of selected single atoms by soft nanoindentation using near contact atomic force microscopy,” Phys. Rev. Lett. 2003. 90; Basu, Guisinger et al., “Room temperature nanofabrication of atomically registered heteromolecular organosilicon nanostructures using multistep feedback controlled lithography,” Applied Physics Letters. 2004. 85:2619; Morita, Sugimoto et al., “Atom-selective imaging and mechanical atom manipulation using the non-contact atomic force microscope,” J. Electron Microsc. 2004. 53:163-168; Ruess, Oberbeck et al., “Toward Atomic-Scale Device Fabrication in Silicon Using Scanning Probe Microscopy,” Nano Letters. 2004. 4; Stroscio and Celotta, “Controlling the Dynamics of a Single Atom in Lateral Atom Manipulation,” Science. 2004. 306:242-247; Duwez, Cuenot et al., “Mechanochemistry: targeted delivery of single molecules,” Nature Nanotechnology. 2006. 1:122-125; Iancu and Hla, “Realization of a four-step molecular switch in scanning tunneling microscope manipulation of single chlorophyll-a molecules,” Proc Natl Acad Sci USA. 2006. 103:13718-21; Ruess, Pok et al., “Realization of atomically controlled dopant devices in silicon,” Small. 2007. 3:563-7; Sugimoto, Pou et al., “Complex Patterning by Vertical Interchange Atom Manipulation Using Atomic Force Microscopy,” Science. 2008. 322:413-417; Randall, Lyding et al., “Atomic precision lithography on Si,” J. Vac. Sci. Technol. B. 2009; Owen, Ballard et al., “Patterned atomic layer epitaxy of Si/Si(001):H,” Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures. 2011. 29:06F201; Wang and Hersam, “Nanofabrication of heteromolecular organic nanostructures on epitaxial graphene via room temperature feedback-controlled lithography,” Nano Lett. 2011. 11:589-93; Kawai, Foster et al., “Atom manipulation on an insulating surface at room temperature,” Nat Commun. 2014. 5:4403) These efforts have generally been limited to simple one- or two-dimensional structures, but the techniques are powerful enough to have already demonstrated basic molecular-scale logic (Heinrich, Lutz et al., “Molecule Cascades,” Science. 2002. 298:1381-1387) and to have inspired commercial efforts to build atomically-precise structures, including work towards quantum computers. (Ruess, Oberbeck et al., “Toward Atomic-Scale Device Fabrication in Silicon Using Scanning Probe Microscopy,” Nano Letters. 2004. 4; Ruess, Pok et al., “Realization of atomically controlled dopant devices in silicon,” Small. 2007. 3:563-7; Randall, Lyding et al., “Atomic precision lithography on Si,” J. Vac. Sci. Technol. B. 2009.)
Previously, atom manipulation was performed using one of three techniques: Feedback Controlled Lithography (FCL), horizontal atom manipulation, or vertical atom manipulation. FCL uses a scanning probe tip to remove atoms (e.g., passivating hydrogens) from a surface, creating chemically-reactive radical patterns on that surface, followed by bulk chemical reactions that take advantage of the new radical sites to create a surface modified at specific atomic locations. Horizontal atom manipulation relies upon dragging atoms across flat surfaces to place them at specific locations, in effect decorating a surface with atomically-precise designs. Vertical atom manipulation, often referred to as mechanosynthesis, includes the deposition of single atoms or molecules, such as CO, as well as vertical atom interchange, which allows a surface and tip atom to be swapped. (Oyabu, Custance et al., “Mechanical vertical manipulation of selected single atoms by soft nanoindentation using near contact atomic force microscopy,” Phys. Rev. Lett. 2003. 90; Morita, Sugimoto et al., “Atom-selective imaging and mechanical atom manipulation using the non-contact atomic force microscope,” J. Electron Microsc. 2004. 53:163-168; Oyabu, Custance et al., “Mechanical Vertical Manipulation of Single Atoms on the Ge(111)-c(2×8) Surface by Noncontact Atomic Force Microscopy,” Seventh International Conference on non-contact Atomic Force Microscopy. Seattle, Wash. 2004.34; Sugimoto, Pou et al., “Complex Patterning by Vertical Interchange Atom Manipulation Using Atomic Force Microscopy,” Science. 2008. 322:413-417; Tarasov, Akberova et al., “Optimal Tooltip Trajectories in a Hydrogen Abstraction Tool Recharge Reaction Sequence for Positionally Controlled Diamond Mechanosynthesis,” J. Comput. Theor. Nanosci. 2010. 7:325-353; Herman, “Toward Mechanosynthesis of Diamondoid Structures: IX Commercial Capped CNT Scanning Probe Microscopy Tip as Nowadays Available Tool for Silylene Molecule and Silicon Atom Transfer,” Journal of Computational and Theoretical Nanoscience. 2012. 9:2240-2244; Herman, “Toward Mechanosynthesis of Diamondoid Structures: X. Commercial Capped CNT SPM Tip as Nowadays Available C2 Dimer Placement Tool for Tip-Based Nanofabrication,” Journal of Computational and Theoretical Nanoscience. 2013. 10:2113-2122; Kawai, Foster et al., “Atom manipulation on an insulating surface at room temperature,” Nat Commun. 2014. 5:4403)
As previously implemented, each of these atom manipulation techniques modifies a single atomic layer on a surface, does so using a very limited palette of reactions and reactants, and cannot manufacture complex, three-dimensional products.
Previous work by the current inventors, including U.S. Pat. No. 8,171,568, U.S. Pat. No. 8,276,211, U.S. Pat. No. 9,244,097, US Patent Application 20150355228, US Patent Application 20160167970 and PCT Application WO/2014/133529 sought to address some of the shortcomings of prior atom manipulation techniques via improved implementations of mechanosynthesis. These references describe various aspects of mechanosynthesis, including a bootstrap process for preparing atomically-precise tips from non-atomically-precise tips, reactions that can be used to build three-dimensional workpieces, methods for ordering such reactions into build sequences, provisioning of feedstock, and disposal of waste atoms.
Nonetheless, room for improvement still exists. Accordingly, it is an object of the invention to improve the manufacturing of three-dimensional workpieces via mechanosynthesis.